Is my machine motion sensitive?

I picked my iMac up a few cm above the desk it sits upon and tilted it a few degrees in all three dimensions and it shut itself off. I am certain that the power cord did not become temporarily disconnected. Other than the power cord the only other peripheral connected was the wired apple keyboard with the wired apple attached. No connections are/were loose. My computer has never sustained any physical damage. It has not shut itself off since, but I have not tried to reproduce the situation since it results in a hard power off. Is this model of the iMac designed to react this way during this situation?